Infill and Alleyways

As mentioned in the Prologue, this blog takes “Houston basically gets it right” as a default starting point for analysis. To that end, any post suggesting we do things different will first look at the status quo and its pros and cons.

So let’s talk about infill development – specifically, townhomes and midrise.

The Status Quo

There is a long-established disconnect in Houston street design. The planning department, which approves plats, requires a 32′ street section, while the engineering department, which approves streets, only requires 27′ (28′ back-to-back). Everyone submits their plats without curblines, and once they’re approved they build the 27′ street. This gives fire trucks a 14′-15′ drive aisle in which to navigate.

As a backup, a separate portion of the city code allows the Fire Department to restrict parking on one side of any street less than 32′, or both sides of any street less than 26′. If the Chief doesn’t like what the engineers approved, he can order the signs himself.

What everyone agrees on is that a residential street right-of-way needs to be 50′ wide. At full buildout, that looks like this:

This is the street that we build everywhere from Montrose to the Katy Prairie.

The Issues

A 50-foot right-of-way is a fine width for single-family suburban development. Many a New Urbanist has fought tooth and nail to allow one-lane, 26-28′ residential streets in juridictions that required more. Some cities in California and the Southwest require streets as wide as 44′. Nationally speaking, our traditional 27′ is pretty darn good.

But that same street is overkill when faced with infill townhomes on 25′ lots. We know this, because nearly every townhome development in Houston is approved with narrow private alleyways. They’re built in Westchase, off Washington, in Oak Forest and The Heights and EaDo, in the FirstSecond, Third, Fourth, and Fifth Wards.

Clearly our developers think this is acceptable (they’re building it), and our planners and engineers think it’s acceptable (they’re approving it). And in the rare case where infill townhomes are built with a full 50′ section, they look out of scale.

The Alternative

Why not allow narrower public streets? A prototype already exists in the historic brick streets of the Fourth Ward. These streets are so beloved by Houstonians, their removal has (as of this writing) been successfully stopped by court order.

A continuous grid of narrow streets would allow for incremental redevelopment in a way that the current gated warrens of easements do not. Someone 30 or 50 years hence could buy up three or four townhomes and build a midrise apartment block, continuing the gradual, organic densification that has made inner-ring Houston so livable already.

A modern cross-section based on the Fourth Ward’s one-way, one-row-of-parking arrangement can preserve the same 14-15′ drive aisle while giving pedestrians a bit more elbow room.

An ideal street for infill development.

The narrower visual field of a 35′ right-of-way slows traffic and helps pedestrians to take ownership of the space. It also reduces land and pavement costs for developers pursuing infill development. This helps encourage the development of a fine-grained, walkable street grid in areas where it’s currently lacking.

Consider the Alleys

Houston currently requires all alleys to be 20 feet of solid concrete. But if we are to allow streets to be 35′, 20′ for an alleyway becomes overkill.

Narrower examples exist here and elsewhere. The unpaved alleys in Montrose are mostly 12′, including the ones behind Numbers and other businesses on Lower Westheimer. Many of the alleys in Fort Worth are 12′. And the City of Olympia‘s standard alley section explicitly specifies a 12’ ROW with two 3-foot tire paths spaced 3 feet apart.

I’m not completely sold on the long-term performance of tire paths. But other designs, like waffle block with a solid central gutter, could convey Houston’s design storm while allowing lesser rain events to percolate into the soil.